Introduce suitable types for handling base64 and hex strings

This commit introduces suitable types for handling `base64` and `hex` strings: `Base64String`, `Base64Binary`, `HexString` and `HexBinary`. 

The old implementation used `String` to represent these types, but the problem with that was, that the length constrains applied to these values were not correct, because it returned the length of the string, not of the actual data. The new types fixes that. 

For convenience we provided two different types for each of the two data formats, one that stores a `Vec<u8>` that contains the decoded data and one that stores the string encoded value as is (in cases where decoding is not needed).

Author: p32blo

Cargo.lock

@@ -24,6 +24,7 @@ homepage = "https://github.com/Bergmann89/xsd-parser"
 [workspace.dependencies]
 anyhow = "1.0"
 base64 = "0.22"
+const-hex = "1.17.0"
 bit-set = "0.8"
 bitflags = "2.7"
 bytesize = "2.3"

Cargo.toml

@@ -14,23 +14,34 @@ repository.workspace = true
 all-features = true
 
 [features]
-default = [ ]
+default = []
 # Enable support for async `quick-xml` de-/serialization
-async = [ "dep:futures", "dep:tokio", "quick-xml/async-tokio" ]
+async = ["dep:futures", "dep:tokio", "quick-xml/async-tokio"]
+
+# Enable support for base64 encoding/decoding
+base64 = ["dep:base64"]
 
 # Enable support for dynamic xml types
-xml = [ "dep:indexmap", "dep:encoding_rs" ]
+xml = ["dep:indexmap", "dep:encoding_rs"]
 
 # Enable support for `quick-xml` de-/serialization
-quick-xml = [ "xml", "dep:quick-xml", "dep:regex", "dep:thiserror" ]
+quick-xml = [
+    "xml",
+    "dep:quick-xml",
+    "dep:regex",
+    "dep:thiserror",
+    "dep:const-hex",
+    "dep:base64",
+]
 
 [dependencies]
 base64 = { workspace = true, optional = true }
+const-hex = { workspace = true, optional = true }
 encoding_rs = { workspace = true, optional = true }
 futures = { workspace = true, optional = true }
 indexmap = { workspace = true, optional = true }
 num = { workspace = true, optional = true }
-quick-xml = { workspace = true, optional = true, features = [ "encoding" ] }
+quick-xml = { workspace = true, optional = true, features = ["encoding"] }
 regex = { workspace = true, optional = true }
 serde = { workspace = true, optional = true }
 thiserror = { workspace = true, optional = true }

xsd-parser-types/Cargo.toml

@@ -10,6 +10,9 @@ use num::{BigInt, BigRational, BigUint};
 #[cfg(feature = "quick-xml")]
 use quick_xml::events::Event;
 
+use crate::quick_xml::{DeserializeBytes, SerializeBytes};
+use crate::xml::NamespacesShared;
+
 #[cfg(feature = "quick-xml")]
 use crate::{
     misc::{Namespace, NamespacePrefix},
@@ -19,10 +22,6 @@ use crate::{
         SerializeHelper, Serializer, WithDeserializer, WithSerializer,
     },
 };
-use crate::{
-    quick_xml::{DeserializeBytes, SerializeBytes},
-    xml::NamespacesShared,
-};
 
 use super::QName;
 
@@ -45,10 +44,10 @@ pub type Unsigned = BigUint;
 pub type Unsigned = usize;
 
 #[cfg(feature = "base64")]
-pub type Base64Binary = Vec<u8>;
+type Base64Binary = crate::xml::Base64Binary;
 
 #[cfg(not(feature = "base64"))]
-pub type Base64Binary = String;
+type Base64Binary = crate::xml::Base64String;
 
 /// Type that represents an `xs:anySimpleType` value.
 #[derive(Debug, Clone)]
@@ -599,14 +598,15 @@ fn parse_base64_binary(bytes: &str) -> Result<Base64Binary, Error> {
 
     Ok(BASE64_STANDARD
         .decode(bytes)
-        .map_err(|_| ErrorKind::InvalidData(bytes.as_bytes().to_vec().into()))?)
+        .map_err(|_| ErrorKind::InvalidData(bytes.as_bytes().to_vec().into()))?
+        .into())
 }
 
 #[inline]
 #[cfg(not(feature = "base64"))]
 #[allow(clippy::unnecessary_wraps)]
 fn parse_base64_binary(s: &str) -> Result<Base64Binary, Error> {
-    Ok(s.to_string())
+    Ok(s.to_string().into())
 }
 
 fn format_vec<X: Display>(items: &[X]) -> String {